If you follow the logic I explain in adjacent thread here
https://forums.scribus.net/index.php/topic,3976.0.html about using ScribusGenerator.py I envisage that you could dynamically change rule book grid cell dimensions by creating a template which has grid cells attributes specified as
%VAR_x1%, %VAR_y1%, %VAR_w1%, %VAR_h1%
%VAR_x2%, %VAR_y2%, %VAR_w2%, %VAR_h2%
etc. and any other attributes you wish to change such as importing images from a repository or directory.
Then all you require to amend are the variables in your master csv before final preview and print.
Another approach would be to create the rulebook cells externally to import. Boxy SVG is a nice utility for this and you can export from Boxy SVG to be imported into Scribus document.